Next to air, water is the element most necessary for survival. A normal adult is 60- to 70-percent water. A person can live without food for almost two months, but without water only for a few days.

A household of five needs at least 120 liters per day to meet basic needs – for drinking, food preparation, cooking and cleaning up, washing and personal hygiene, laundry, house cleaning, according to the Washington-based Worldwatch Institute, a global environmental group.

We need at least 24 liters of water daily our one liter per hour. Even when we are breathing, we still need water. “Our lungs must be moist to take in oxygen and excrete carbon dioxide,” wrote Leroy Perry in an article. “It is possible to lose half a liter of liquid each day just by exhaling.”

That’s how important water is. While 70 percent of the earth’s surface is water, only three percent of it is considered fresh water – and almost all of that three percent is inaccessible for human use. About three-quarters of all fresh water on this planet is locked away in the form of ice caps and glaciers located in polar areas far from most human habitation.

In all, only about 0.01 percent of the world’s total water supply is considered available for human use on a regular basis. “If the world’s freshwater supply amounted to the contents of a bathtub,” explains Don Hinrichsen, an award-winning American environmental journalist, “the amount easily accessible to humanity would fill a thimble.”

And this accessible water are fast deteriorating around the world. In the Philippines, rapid urbanization and surging population are putting the country at risk of an impending water crisis.

In 2007, the Asian Development Bank (ADB) sounded the alarm. The study said that unless things are turned around, river and groundwater systems will fail by 2025. Only about 33 percent of river systems are still suitable as a supply source and up to 58 percent of groundwater sources are now contaminated.

The country has 421 principal rivers. During dry months, 16 rivers are touted to be “biologically dead,” according to the ADB study. In addition, it warned that water availability could be “unsatisfactory” in eight of the country’s 19 major river basins.

The ability of groundwater – or water held underground or in pores and crevices in rocks – to meet future water demand was also projected to be very limited, amounting to only 20 percent of the total water requirement in the country’s nine main urban centers by 2025.

“Groundwater is used for drinking by about 50 percent of the people in the country,” said a report from the World Bank. Forty-nine percent of groundwater is consumed by the domestic sector and the remaining is shared by agriculture (32 percent), industry (15 percent), and other sectors. “About 60 percent of the groundwater extraction is without water-right permits, resulting in indiscriminate withdrawal,” the bank deplored.

Depletion of groundwater resources is already an increasing problem in Metro Manila and Metro Cebu at present, the ADB study pointed out. In Davao City, the lowering of the piezometric water levels was observed in 15 of the 35 operating wells. “With almost all wells in the Davao City Well District located below sea level, the aquifer will be particularly susceptible to saline intrusion if the decline in piezometric level continues,” the World Bank warned.

Metro Manila, Metro Cebu, and Davao were among the nine major cities listed as “water-critical areas” in a study by the Japan International Cooperation Agency in 1991. The other seven cities were Angeles, Baguio, Bacolod, Cagayan de Oro, Iloilo, and Zamboanga.

“There is no more water on earth now than there was 2,000 years ago, when the population was less than three percent of its current size,” wrote Hinrichsen. The ADB study agreed: “The rapid urbanization of the Philippines, with more than two million persons being added to the urban population annually, is having a major impact on water resources.”

Compounding the problem is the deterioration of water resources due to pollution. “Water quality is poorest in urban areas, the main sources of pollution being untreated discharges of industrial and municipal wastewater,” the ADB said.

The ADB study found out that 48 percent of water pollution arise from domestic use, 37 percent from agricultural waste, and 15 percent from industrial waste. Even more alarming is this fact: “The majority of solid waste disposal and landfill sites are poorly operated and maintained, permitting leachate to pollute some water resources.”

Because most people are now health conscious, they prefer to drink bottled water. Consumers across the globe now spend an estimated US$35 billion a year on this kind of water. Although its contents might appear the same everywhere, bottled water essentially comes in three different forms: natural mineral water, spring water, and purified water.

Most consumers assume that water purchased in a bottle is better regulated, more pure, or safer than most tap water. But is it? “While the sources of these waters are protected from pollution, since the water is not disinfected it can contain naturally occurring bacteria,” writes The Green Guide’s Paul McRandle. “And though bottlers guard against it, contamination is always possible.”

In the United States, the Natural Resources Defense Council (NRDC) tested more than 1,000 bottles of water from 103 brands. While noting that most bottled water is safe, the NRDC found that at least one sample of a third of the brands contained bacterial or chemical contaminants, including carcinogens, in levels exceeding industry standards. In India, tests by the Center for Science and Environment found high pesticides levels in sampled bottled waters.

“The world has got a very big water problem,” says Sir Crispin Tickell, former British ambassador to the United Nations and one of the organizers of the 1992 Earth Summit in Rio de Janeiro. “It will be the progenitor of more wars than oil.”

“Water isn’t just a commodity. It is a source of life,” wrote Sandra Postel, director of the Global Water Policy Project in Amherst, Massachusetts. But just how much water should each person drink?